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這是我到目前爲止有:如何在Scala中編寫'通用'mergesort?
def mergesort[T <: Ordered[T]](elements : List[T]) : List[T] = {
def merge(first : List[T], second : List[T]) : List[T] = (first, second) match {
case (Nil, _) => second
case (_, Nil) => first
case (x :: xs, y :: ys) => if (x < y) x :: merge(xs, second) else y :: merge(first, ys)
}
if (elements.isEmpty) Nil
else {
val length = elements.length
val (firstHalf, secondHalf) = elements.splitAt(length/2)
merge(mergesort(firstHalf), mergesort(secondHalf))
}
}
我遇到的問題是,這種失敗
mergesort(List(1, 3, 6, 3, 1, 0))
error: inferred type arguments [Int] do not conform to method mergesort's type parameter bounds [T <: Ordered[T]]
mergesort(List(1, 3, 6, 3, 1, 0))
^
有什麼辦法,使這項工作被下令所有類型?我雖然斯卡拉會有某種隱式轉換爲'富'整數類型,我認爲會有Ordered
特質。
看到這裏的一些技巧:http://stackoverflow.com/questions/6929637/selection-sort-generic-type-implementation – huynhjl 2012-03-24 01:34:35